Why Is My Floor Drain Backflowing Due to Upstairs Drainage Issues?

The issue of sewage backflow from floor drains can be quite a headache for many homeowners. So, why does backflow occur in your floor drain when the upstairs neighbors drain water? Let's take a look.

Why does backflow occur in my floor drain when the upstairs drains water?

This situation is often caused by a blockage between your downpipe and the downpipe leading to the floor below. In this case, whether there is water leakage from above or water is draining, your floor drain will experience backflow. The only way to prevent backflow is to resolve the blockage issue.

How to deal with floor drain backflow

First, remove the filtering screen from the floor drain. If it’s a ball-type drain, you will need to take out the entire drain to clean it. When disassembling, you can use a cutting machine to cut through the surrounding tiles and cement. It’s best to spray water while cutting to prevent the tiles from cracking or breaking, while also allowing for better, straighter cuts. This helps minimize further damage and facilitates future restoration work.

Once the cutting line is completed, you can use a hammer to break open the cut area. This will help remove the drain without damaging it. After loosening, you should be able to take out the floor drain more easily.

After removing the drain, you will have a clear view of the sewage pipe. Take a piece of round wood, wrap one end with a cloth, and insert it into the sewage pipe to effectively clean the surrounding grime. This method also helps prevent any surrounding cement or gravel from falling into the sewage pipe, avoiding secondary blockages.

Use the round wood to push and pull repeatedly. The pressure created in this process will help clear away any blockages. Once the blockage is cleared, you will need to reinstall the floor drain. At this time, you will need cement mortar and waterproofing materials; mix them together and apply them around the floor drain.

Next, place the floor drain back into the sewage pipe and fit it in place. Be sure to have the drain slightly lower (by about 1mm) than the surrounding area to ensure water flows towards it. After that, you can tile around the drain. After about half an hour, or when the mixture has initially set, you can reinstall the filtering screen.

In summary：you should now have a better understanding of why backflow occurs in your floor drain when the upstairs drains water. If you want to learn more related knowledge, feel free to follow our website!